Self-priming pump



Jan. 8, 1963 s. B. MCFARLINS 3,072s063 SELF-PRIMING PUMP Filed April 22. 1960 i v a"! l IN VENTOR. 2 \sr/m/zey .e. MQ AAAW array/As s United States Patent Office 3,072,053 Patented Jan. 8, 1963 3,072,063 SELF-PRIMING PUMP Stanley B. McFarlin, .leromesville, Ohio, assignor to The Gorman-Rupp Company, Mansfield, Ohio, a corporation of ()hio Filed Apr. 22, 196i), Ser. No. 24,020 6 Claims. (Cl. 163-113) This invention relates to the pumping art and is particularly concerned with a centrifugal pumping device provided with means greatly minimizing, or substantially preventing, wear due to abrasives between the front side of the impeller and the opposed surface of the front wall of the pump casing.

In centrifugal pumps as constructed heretofore, particularly those handling liquids containing abrasive sub stances in small size particles, considerable Wear occurs between the front wall of the casing and the opposed side of the impeller. When the impeller blades extend beyond the periphery of the impeller disc, such wear becomes excessive. Either condition results in loss of pump efficiency because liquid propelled into the volute by the impeller blades can reenter the inlet to the pumping chamber by way of the space between the front side of the impeller blades and the opposed surfaces of the front wall of the pump casing. To the extent that such recirculation occurs, the efficiency of the pump is diminished. When wear occurs between the rear side of the impeller blades and the opposed rear wall of the casing, the liquid may not recirculate into the inlet to the pumping chamber and hence, water flowing through the space afforded by such wear does not impair the efficiency of the pump to a serious extent.

The present invention aims substantially to prevent the wear between the front side of the impeller blades and the front wall of the pump housing, and this object is attained by the novel combination of elements embodied in the present invention.

This invention will be better understood by those skilled in the art from the following specification accompanying the drawinga in which a preferred embodiment of the invention is disclosed.

FIGURE 1 is a vertical, sectional view of a pumping device embodied in the present invention taken on line 1-1 of FIGURE 2;

FIGURE 2 is a vertical, sectional view of the device embodying the present invention taken on line 2-2 of FIGURE 1;

' FIGURE 3 is a fragmentary, cross-sectional view taken on line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged fragmentary view showing the part of the joint between the front and back walls of the pump casing; and,

FIGURE 5 is a fragmentary, sectional view taken on line 55 of FIGURE 4 and showing the inter-engaging relationship of the front and back walls of the pump casing.

FIGURES l and 2 a housing 1 composed of a front wall and back wall. The front wall 2 has laterally projecting bottom edge wall 3, upright edge Walls 4 and 5 and top edge wall 6 and a laterally extending wall '7 surrounding a fluid inlet 8. Edge wall 4 is provided with a fluid outlet 9. Edge wall 6 is smoothly curved opposite outlet 9 for a purpose presently to be described. The housing also includes a back wall 10 which is bolted against the rear faces of the edge walls and is provided with an opening 11 through which an impeller shaft 12 extends. The back wall 10 is attached to a support 15, as by cap screws 16, and this support 15 may be mounted on any suitable base 26.

A centrifugal pump casing designated as an entirety by reference character 21 is positioned within the housing 1. This casing includes a front wall 22, a back wall 23 and a volute wall 24. The front wall 22 and volute wall 24 define a volute chamber 28 and a fluid inlet opening 29. The back wall 23 and the front wall 22 define an impeller chamber 27 which, as may be seen by referring to FIGURE 2, is the space within the diameter of the outer edges of the impeller blades.

The back wall 23 of the pump has an axially extending annular wall 30 which bears on back Wall 10 of the housing and spaces the pump casing therefrom. The back wall 23 of the casing is secured to the back wall 10 of the housing by any suitable means, such for example as the screws 31, one of which is shown in FIG- URE 1. The parts constituting the pump casing are so proportioned with respect to the space between the back wall 10 and the inner end of annular wall 7 that, when the pump is assembled in the housing, the front wall 22 of the casing will engage and press a gasket against the inner end of wall 7 while the annulus 30 engages the back wall 10. Thus, walls 7 and 39 serve to space the casing away from the front and rear walls of the housing. In other words, annular wall 30 on the pump casing and annular wall 7 on the front wall of the housing serve to provide a space for fluid entirely surrounding the pump casing. It will be understood that when the front and back walls of the housing are bolted together the separate parts constituting the pump casing will thereby be clamped together and maintained in assembled position.

The volute of the pump casing terminates in a discharge end 36 which extends upwards from the point of beginning of the volute wall 24 and gradually enlarges in area as it progresses, and its terminus is in such relation to the curved portion of edge wall 6 that any movement of fluid from the discharge 36 is caused to flow towards the fluid outlet '9.

The shaft 12 is provided with a shaft seal consisting of several parts, designated collectively at 40', which seal may be of any suitable or conventional type. Impeller disc is affixed to the inner end of shaft 12 with the casing 21, and this disc is provided with a plurality of curved impeller blades 46 which extend outwardly to points beyond the periphery of disc 45. The pumping device of FIGURES 1 and 2 is mounted with the longitudinal axis of shaft 12 in a substantially horizontal position, and with fluid outlet 9 and the fluid outlet 36 of the volute lying above the shaft, substantially as shown in FIGURE 2. A screw plug 47 is provided for a threaded hole in the top edge 6 of the housing for supplying initial priming liquid and for inspection purposes, and a similar screw plug 48 is provided for a threaded opening in the front wall 2 of the housing near its bottom for drainage purposes.

The fluid inlet opening 8 has its lowermost surface disposed above the longitudinal center line of the shaft 12. This lowermost surface of inlet 8 serves as a drainage level below which liquid will not drain out of the housing when the rotation of the impeller ceases. In other words, the surface level of the liquid in housing 1 and casing 21 will not fall below the level indicated at 50 in FIGURE 1 when the impeller is at rest.

The back wall 23 of the impeller casing is shaped to provide, in cooperation with the volute wall 24, a passage 51 which extends from the outer periphery of volute wall 24 upwardly and inwardly into the impeller chamber 27 at an acute angle to the plane of the impeller and tangentially to the periphery of the impeller and against the direction of rotation of the impeller and the flow of liquid in the volute.

As is shown in FIGURES 4 and 5, the back wall 23 of the pump casing is provided with a notch 64 into which a lug 61 on the volute wall 24 extends for the purpose of positioning these two walls relative to one another and against relative rotation. As FIGS. 1, 4 and 5 show the casing walls have two sets of mutually engaging annular surfaces by which casing wall 22 is positioned radially and axially by the casing wall 23. One set of these surfaces consists of the cylindrical concentric surfaces on wall 23 and on part 24 of wall 22. The other set consists of the axially abutting surfaces including notch 60 and lug 61.

The above described apparatus operates substantially as follows:

Let it be assumed that it is desired to pump liquid in through inlet 8 and out through outlet 9, and that the surface of liquid in housing 1 and casing 21 is at the level indicated at 50 with gas filling the space within the casing above the liquid level. The pump shaft 12 is rotated ata velocity great enough for the impeller blades 46 to cause the liquid in the pump casing to move outwardly into the volute chamber 28 and to flow therein out through outlet 36 and into the interior of the housing. Some of the gas in the casing will be mixed with the liquid being moved into and through the volute chamber and will be carried into the space above the volute out let 36 where the gas will separate from the liquid and may escape through outlet 9 with the liquid returning to the bottom part of the housing 1. During this stage of operations and as soon as the liquid level in the easing falls below the level in the housing, liquid will flow into the impeller chamber through passage 51. In this manner, the liquid recirculates from the housing through the pump casing and back into the housing; and this action continues so long as there is any gas in the casing. Since the rotation of the impeller removes gas from within the casing, a vacuum condition is created in the casing which causes gas in the inlet 8 and a pipe connected thereto to flow into the casing. Such a pipe will fill with liquid as the gas is thus Withdrawn from it. The casing 21 and the housing 1 will eventually become completely filled with liquid, and liquid will thereafter be pumped in through the inlet 8 and out through outlet 9. This completes the priming of the pump.

When the pump has thus been primed, the direction of flow of liquid in passage 51 will be reversed, whereupon part of the liquid propelled by the impeller will flow out of the casing through the volute outlet 36 and part will flow through passage 51. However, fluid flowing from both of these outlets will flow out of housing 1 through outlet 9.

It will be understood that during the priming stage, the ingress of liquid through passage 51 into the back portion of the impeller chamber greatly reduces the usual amount of wear, due to abrasives, between the front edges of impeller blades 4-6 and wall 22. This reduction in wear is due to the fact that such liquid will carry its solids into contact with the rear edges of the blades. Thus any wear between the impeller and easing, during priming, will be substantially restricted to the rear side of the impeller and the opposed surface of the rear Wall. Since liquid which escapes from the volute into the space between the rear edges of the blades and the opposed surface of the rear wall of the casing cannot return within the casing to the inlet to the impeller chamber, the efficiency of the pump will be maintained regardless of the extent of wear between the impeller and the opposed surface of the back wall of the pump casing.

Having thus described this invention in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same, and having set forth the best mode contemplated of carrying out this invention, I state that the subject matter which I regard as being my invention is particularly pointed out and distinctly claimed in what is claimed, it being understood that equivalents or modifications of, or substitutions for, parts of the above specifically described embodiment of the invention may be made without departing from the scope of the invention as set forth in what is claimed.

What is claimed is:

1. A self-priming centrifugal pumping device comprismg:

(a) a housing including a front wall, a back wall and means for clamping the two walls together at their peripheries, said housing defining therewithin a chamber for a centrifugal pump,

(b) a centrifugal pump in said chamber, said pump including a casing having a front side wall, a rear side wall and a volute wall between the peripheries of said walls,

(c) said casing defining animpeller chamber and a volute chamber surrounding the impeller chamber,

(d) the front wall of the housing and the front side wall of said casing having inlets for the flow of a liquid into said impeller chamber,

(e) an impeller in said chamber,

(f) a shaft extending through the rear wall of the housing and the rear side wall of the casing and attached to said impeller,

(g) said rear side wall of the casing only having a passage extending upwardly and inwardly therethrough at an acute included angle to the plane of rotation of the impeller from adjacent to the bottom of said housing chamber and opening directly into the impeller chamber above the lower edge of the impeller and below the surface of liquid in said chamber when the impeller is at rest, and means spacing the front and back walls of the pump casing from the front and back walls of the housing, respectively, said spacing means serving when the front and rear walls of the housing are clamped together at their peripheries, to press the front and rear walls of the pump casing against one another in assembled operative position and to maintain them in such position during use.

2. The combination of elements set forth in claim 1 in which the means for spacing the pump from the front and back walls of the housing includes an annular wall between the front wall of the housing and the front side wall of the casing about said inlet, and an annular wall between the rear wall of the housing and the rear side wall of the casing around said shaft.

3. A self-priming centrifugal pumping device comprismg:

(a) a housing including a front wall, a back wall and means for clamping the two walls together at their peripheries, said housing defining therewithin a chamber for liquid,

(b) a centrifugal pump casing within said chamber and spaced from the walls of the housing and including two walls defining therebetween an impeller chamher and a volute,

(c) an impeller in said casing and a shaft attached to the impeller and extending through one of said casing walls and through the adjacent wall of the housing,

(d) the first of the casing walls being fixed to one of the housing walls and being positioned thereby relative to the shaft and impeller,

(e) two sets of mutually engaging annular surfaces on said casing walls for positioning the second casing wall radially and axially relative to said first wall and to said impeller,

(f) and means for holding said casing walls in an assembled position including an annulus provided on one of said housing walls and engaging and pressing said second casing wall against said first wall under compressive forces exerted by the adjacent housing wall when the housing walls are clamped together.

4. The combination of elements set forth in claim 3 in which the said annulus is integral with the adjacent housing wall.

5. The combination of elements set forth in claim 3 in which the first casing Wall has an integral annular wall extending around said shaft and attached to the adjacent housing Wall and the said annulus extends around the inlet into said casing and is integral with the adjacent housing wall.

6. The combination of elements set forth in claim 3 in which the said annular surfaces are concentric cylindrical engaging surfaces on the casing Walls to position the second casing Wall coaxially with the impeller and abutting surfaces disposed at an angle to the shaft to position the second casing Wall longitudinally relative to the first casing wall.

References (Cited in the file of this patent UNITED STATES PATENTS Jacobsen Feb. 6, 1934 Bird Nov. 20, 1934 Bargen May 19, 1936 Stratton Dec. 10, 1940 La Bour June 3, 1941 Mann Feb. 10, 1953 Rupp July 24, 1956 FOREIGN PATENTS Great Britain May 13, 1953 France Nov. 23, 1951 France Dec. 27, 1956 

1. A SELF-PRIMING CENTRIFUGAL PUMPING DEVICE COMPRISING: (A) A HOUSING INCLUDING A FRONT WALL, A BACK WALL AND MEANS FOR CLAMPING THE TWO WALLS TOGETHER AT THEIR PERIPHERIES, SAID HOUSING DEFINING THEREWITHIN A CHAMBER FOR A CENTRIFUGAL PUMP, (B) A CENTRIFUGAL PUMP IN SAID CHAMBER, SAID PUMP INCLUDING A CASING HAVING A FRONT SIDE WALL, A REAR SIDE WALL AND A VOLUTE WALL BETWEEN THE PERIPHERIES OF SAID WALLS, (C) SAID CASING DEFINING AN IMPELLER CHAMBER AND A VOLUTE CHAMBER SURROUNDING THE IMPELLER CHAMBER, (D) THE FRONT WALL OF THE HOUSING AND THE FRONT SIDE WALL OF SAID CASING HAVING INLETS FOR THE FLOW OF A LIQUID INTO SAID IMPELLER CHAMBER, (E) AN IMPELLER IN SAID CHAMBER, (F) A SHAFT EXTENDING THROUGH THE REAR WALL OF THE HOUSING AND THE REAR SIDE WALL OF THE CASING AND ATTACHED TO SAID IMPELLER, (G) SAID REAR SIDE WALL OF THE CASING ONLY HAVING A PASSAGE EXTENDING UPWARDLY AND INWARDLY THERETHROUGH AT AN ACUTE INCLUDED ANGLE TO THE PLANE OF ROTATION OF THE IMPELLER FROM ADJACENT TO THE BOTTOM OF SAID HOUSING CHAMBER AND OPENING DIRECTLY INTO THE IMPELLER CHAMBER ABOVE THE LOWER EDGE OF THE IMPELLER AND BELOW THE SURFACE OF LIQUID IN SAID CHAMBER WHEN THE IMPELLER IS AT REST, AND MEANS SPACING THE FRONT AND BACK WALLS OF THE PUMP CASING FROM THE FRONT AND BACK WALLS OF THE HOUSING, RESPECTIVELY, SAID SPACING MEANS SERVING WHEN THE FRONT AND REAR WALLS OF THE HOUSING ARE CLAMPED TOGETHER AT THEIR PERIPHERIES, TO PRESS THE FRONT AND REAR WALLS OF THE PUMP CASING AGAINST ONE ANOTHER IN ASSEMBLED OPERATIVE POSITION AND TO MAINTAIN THEM IN SUCH POSITION DURING USE. 